arXiv subjects

Dave Auckly

Publications and source records attributed to Dave Auckly.

At least 19 recordsLinked to original sources

arXiv2025

Exotic families of embeddings

We construct a number of topologically trivial but smoothly non-trivial families of embeddings of 3-manifolds in 4-manifolds. These include embeddings of homology spheres in $S^4$ that are not isotopic but have diffeomorphic complements, and families (parameterized by high-dimensional spheres) of embeddings of any 3-manifold that embeds in a blown-up K3 surface. In each case, the families are constructed so as to be topologically trivial in an appropriate sense. We also illustrate a general technique for converting a non-trivial family of embeddings into a non-trivial family of submanifolds.

math.GT↗

arXiv2025

Families of diffeomorphisms, embeddings, and positive scalar curvature metrics via Seiberg-Witten theory

We construct infinite rank summands isomorphic to $\mathbb{Z}^\infty$ in the higher homotopy and homology groups of the diffeomorphism groups of certain $4$-manifolds. These spherical families become trivial in the homotopy and homology groups of the homeomorphism group; an infinite rank subgroup becomes trivial after a single stabilization by connected sum with $S^2 \times S^2$. The stabilization result gives rise to an inductive construction, starting from non-isotopic but pseudoisotopic diffeomorphisms constructed by the second author in 1998. The spherical families give $\mathbb{Z}^\infty$ summands in the homology of the classifying spaces of specific subgroups of those diffeomorphism groups. The non-triviality is shown by computations with family Seiberg-Witten invariants, including a gluing theorem adapted to our inductive construction. As applications, we we obtain infinite generation for higher homotopy and homology groups of spaces of embeddings of surfaces and $3$-manifolds in various $4$-manifolds, and for the space of positive scalar curvature metrics on standard PSC $4$-manifolds.

math.GT↗

arXiv2023

Counting Regions in Billiard Trajectories

This paper explores the number of parallelograms that appear in a billiard path that enters one corner of a rectangle and leaves a second corner of a rectangle as a function of the normalized dimensions of the rectangle.

math.HO↗

arXiv2020

Equivariant hyperbolization of $3$-manifolds via homology cobordisms

The main result of this paper is that any $3$-dimensional manifold with a finite group action is equivariantly, invertibly homology cobordant to a hyperbolic manifold; this result holds with suitable twisted coefficients as well. The following two consequences motivated this work. First, there are hyperbolic equivariant corks (as defined in previous work of the authors) for a wide class of finite groups. Second, any finite group that acts on a homology $3$-sphere also acts on a hyperbolic homology $3$-sphere. The theorem has other applications, including establishing the existence of an infinite number of hyperbolic homology spheres with a free $Z_p$ action that does not extend to any contractible manifold. A non-equivariant version yields an infinite number of hyperbolic integer homology spheres that bound integer homology balls but do not bound contractible manifolds. In passing, it is shown that the invertible homology cobordism relation on $3$-manifolds is antisymmetric.

math.GT↗

arXiv2020

Folklore, the Borromean rings, the icosahedron, and three dimensions

There is a relationship between the Borromean rings, the icosahedron and something called the Poincaré homology sphere. This relationship is explored in a wandering path that introduces fundamental ideas from topology and a geometric construction of an icosahedral compound of octahedra. This exploration results in proofs that the orientation-preserving symmetry group of an icosahedron is the alternating group of five symbols, the fact that the Borromean rings are linked, and background related to the Poincaré conjecture. This is an exposition of known results aimed at undergraduates.

math.HO↗

arXiv2017

Isotopy of surfaces in 4-manifolds after a single stabilization

Any two homologous surfaces of the same genus embedded in a smooth 4-manifold X with simply-connected complements are shown to be smoothly isotopic in the connected sum of X and the product of a 2-sphere with itself, if the surfaces are ordinary, and in the connected sum of X with the non-trivial sphere bundle over the sphere if they are characteristic.

math.GT↗

arXiv2016

Equivariant Corks

For suitable finite groups G, we construct contractible 4-manifolds C with an effective G-action on $\partial C$ whose associated pairs (C,g) for all $g \in G$ are distinct smoothings of the pair $(C,\partial C)$. Indeed C embeds in a 4-manifold so that cutting out C and regluing using distinct elements of G yield distinct smooth 4-manifolds.

math.GT↗

arXiv2014

Stable isotopy in four dimensions

We construct infinite families of topologically isotopic but smoothly distinct knotted spheres in many simply connected 4-manifolds that become smoothly isotopic after stabilizing by connected summing with $S^2 \times S^2$, and as a consequence, analogous families of diffeomorphisms and metrics of positive scalar curvature for such 4-manifolds. We also construct families of smoothly distinct links, all of whose corresponding proper sublinks are smoothly isotopic, that become smoothly isotopic after stabilizing.

math.GT↗

arXiv2014

Two Fold Branched Covers

Many three dimensional manifolds are two-fold branched covers of the three dimensional sphere. However, there are some that are not. This paper includes exposition about two-fold branched covers and many examples. It shows that there are three dimensional homology spheres that do not two-fold branched cover any manifold, ones that only two-fold branched cover the three dimensional sphere, ones that just two-fold branched cover a non-trivial manifold, and ones that two-fold branched cover the sphere and non-trivial manifolds. When a manifold is surgery on a knot, the possible quotients via involutions generically correspond to quotients of the knot. There can however be a finite number of surgeries for which there are exceptional additional symmetries. The included proof of this result follows the proof of Thurston's Dehn surgery theorem. The paper also includes examples of such exceptional symmetries. Since the quotients follow the behavior of knots a census of the behavior for knots with less than eleven crossings is included.

math.GT↗

arXiv2013

Triangles, Rotation, a Theorem and the Jackpot

This is an expository paper designed to introduce undergraduates to the Atiyah-Singer index theorem 50 years after its announcement. It includes motivation, a statement of the theorem, an outline of the easy part of the heat equation proof. It includes counting lattice points and knot concordance as applications.

math.HO↗

arXiv2009

Introduction to the Gopakumar-Vafa Large N Duality

Gopakumar-Vafa large N duality is a correspondence between Chern-Simons invariants of a link in a 3-manifold and relative Gromov-Witten invariants of a 6-dimensional symplectic manifold relative to a Lagrangian submanifold. We address the correspondence between the Chern-Simons free energy of S^3 with no link and the Gromov-Witten invariant of the resolved conifold in great detail. This case avoids mathematical difficulties in formulating a definition of relative Gromov-Witten invariants, but includes all of the important ideas. There is a vast amount of background material related to this duality. We make a point of collecting all of the background material required to check this duality in the case of the 3-sphere, and we have tried to present the material in a way complementary to the existing literature. This paper contains a large section on Gromov-Witten theory and a large section on quantum invariants of 3-manifolds. It also includes some physical motivation, but for the most part it avoids physical terminology.

math.GT↗

arXiv2007

The Pontrjagin-Hopf invariants for Sobolev maps

Subtle issues arise when extending homotopy invariants to spaces of functions having little regularity, e.g., Sobolev spaces containing discontinuous functions. Sometimes it is not possible to extend the invariant at all, and sometimes, even when the formulas defining the invariants make sense, they may not have expected properties (e.g., there are maps having non-integral degree). In this paper we define a complete set of homotopy invariants for maps from 3-manifolds to the 2-sphere and show that these invariants extend to finite Faddeev energy maps and maps in suitable Sobolev spaces. For smooth maps, our description is proved to be equivalent to Pontrjagin's original homotopy classification from the 1930's. We further show that for the finite energy maps the invariants take on exactly the same values as for smooth maps. We include applications to the Faddeev model. The techniques that we use would also apply to many more problems and/or other functionals. We have tried to make the paper accessible to analysts, geometers and mathematical physicists.

math-ph↗

arXiv2007

The number of smooth 4-manifolds with a fixed complexity

One can define the complexity of a smooth 4-manifold as the minimal sum of the number of disks, strands and crossings in a Kirby diagram. Martelli proved that the number of homeomorphism classes of complexity less than n grows as $n^2$. In this paper we prove that the number of diffeomorphism classes grows at least as fast as $n^{c\sqrt[3]{n}}$. Along the way we construct complete kirby diagrams for a large family of knot surgery manifolds.

math.GT↗

arXiv2007

Solving the quartic with a pencil

This expository paper presents the general solution of a quartic equation as a jump off point to introduce Lefschetz fibrations. It should be accessible to a broad audience.

math.HO↗

arXiv2004

Fermionic quantization and configuration spaces for the Skyrme and Faddeev-Hopf models

The fundamental group and rational cohomology of the configuration spaces of the Skyrme and Faddeev-Hopf models are computed. Physical space is taken to be a compact oriented 3-manifold, either with or without a marked point representing an end at infinity. For the Skyrme model, the codomain is any Lie group, while for the Faddeev-Hopf model it is $S^2$. It is determined when the topology of configuration space permits fermionic and isospinorial quantization of the solitons of the model within generalizations of the frameworks of Finkelstein-Rubinstein and Sorkin. Fermionic quantization of Skyrmions is possible only if the target group contains a symplectic or special unitary factor, while fermionic quantization of Hopfions is always possible. Geometric interpretations of the results are given.

hep-th↗

arXiv2004

Analysis of the Faddeev model

In this paper we consider a generalization of the Faddeev model for the maps from a closed three-manifold into the two-sphere. We give a novel representation of smooth $ S^2$-valued maps based on flat connections. This representation allows us to obtain an analytic description of the homotopy classes of $ S^2$-valued maps that generalizes to Sobolev maps. It also leads to a new proof an old theorem of Pontrjagin. For the generalized Faddeev model, we prove the existence of minimizers in every homotopy class.

math-ph↗

arXiv2003

Topologically knoted Lagrangians in simply connected four manifolds

Vidussi was the first to construct knotted Lagrangian tori in simply connected four dimensional manifolds. Fintushel and Stern introduced a second way to detect such knotting.This note demonstrates that similar examples may be distinguished by the fundamental group of the exterior.

math.SG↗

arXiv2002

Holonomy and Skyrme's model

In this paper we consider two generalizations of the Skyrme model. One is a variational problem for maps from a compact three-manifold to a compact Lie group. The other is a variational problem for flat connections. We describe the path components of the configuration spaces of smooth fields for each of the variational problems. We prove that the invariants separating the path components are well-defined for (not necessarily smooth) fields with finite Skyrme energy. We prove that for every possible value of these invariants there exists a minimizer of the Skyrme functional. Throughout the paper we emphasize the importance of holonomy in the Skyrme model. Some of the results may be useful in other contexts. In particular, we define the holonomy of a distributionally flat $ L^2_{loc} $ connection; the local developing maps for such connections need not be continuous.

math-ph↗